Apparatus for a syngas cooler and method of maintaining the same

ABSTRACT

A quench ring assembly for a high-temperature vessel includes a main structural sub-assembly coupled to at least one lower wall tube. The quench ring assembly also includes a flow control sub-assembly coupled to the main structural sub-assembly and extending circumferentially therethrough. The quench ring assembly further includes a wear sub-assembly removably coupled to the main structural sub-assembly. The wear sub-assembly includes a heat shield canopy extending over the flow control sub-assembly.

BACKGROUND OF THE INVENTION

This invention relates generally to synthesis gas, or syngas, coolersfor use in a gasifier system, and, more specifically, to a quench ringassembly for use with a syngas cooler.

Many known gasifier systems include a reactor that defines a reactionchamber in which a fuel mixture is gasified to form a hot product gasand liquefied slag flows downward therefrom. A quench chamber holding awater bath is positioned in the reactor to receive and cool the hotproduced effluent. A constricted throat that couples the reactionchamber with the quench chamber directs a stream of the effluent througha dip tube which defines a guide passage to conduct the effluent intothe water bath. A toroidally-shaped quench ring is positioned radiallyinward of the dip tube to direct a water stream onto the dip tube'sguide surface.

Most known quench rings include a high-wear hot face portion that isdirectly exposed to the gasifier's high-temperature and erosiveconditions by virtue of the hot product gas which makes contact with hotface portion as the gas is channeled from the reaction chamber to thewater bath. While the relatively cooler liquid flowing through thequench ring onto the dip tube's guide surface at least partiallymitigates localized high temperatures, significant stresses and strainsare induced in the hot face portion of the quench ring. Suchthermally-induced stresses and strains facilitate increasing areplacement frequency of the hot face portion due to formation of cracksand fissures along the exposed surface. The hot face portion istypically a portion of a larger structural member, e.g., aremovable/replaceable quench ring metal apron that facilitates providingthe sacrificial wear surface. In addition, the apron is coupled to aplurality of cooling fluid inlet flanges, typically through welds, suchflanges being aligned and coupled with fluid supply lines throughfittings, e.g., Grayloc® fittings. Therefore, replacement and/orrefurbishment of the hot face portion requires removing the gasifierfrom service, mobilizing a sizable maintenance crew, uncoupling theflanges, and removing the quench ring in its entirety in sections.During the replacement and/or refurbishment activities that occuroutside of the gasifier, the hot face portion is repaired and/orreplaced. However, upon replacement of the quench ring sections into thegasifier, the quench ring metal apron and flanges may not be in theiroriginal positions and orientations and may not align properly.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, a quench ring assembly for a high-temperature vessel isprovided. The quench ring assembly includes a main structuralsub-assembly coupled to at least one lower wall tube. The quench ringassembly also includes a flow control sub-assembly coupled to the mainstructural sub-assembly and extending circumferentially therethrough.The quench ring assembly further includes a wear sub-assembly removablycoupled to the main structural sub-assembly. The wear sub-assemblyincludes a heat shield canopy extending over the flow controlsub-assembly.

In another aspect, a method of maintaining a synthesis gas (syngas)cooler for use within a gasifier system is provided. The method includesbreaking at least a portion of at least one of a circumferentialnon-bonded joint and a circumferential seam weld on a quench ringassembly that couples a wear sub-assembly to a main structural member ata circumferential coupling site. The method also includes removing atleast a portion of the wear sub-assembly and a flow control sub-assemblycoupled thereto from the main structural member. The method furtherincludes providing at least one replacement portion of the wearsub-assembly. The method also includes positioning the at least onereplacement portion of the wear sub-assembly to extend over at least aportion of the flow control sub-assembly and to abut the main structuralmember proximate the circumferential coupling site. The method furtherincludes coupling the at least one replacement portion of the wearsub-assembly to the main structural member.

In a further aspect, a gasifier system is provided. The gasifier systemincludes at least one gasifier configured to produce a synthesis gas(syngas). The gasifier system also includes at least one syngas coolercoupled to at least one lower wall tube. The at least one syngas coolerincludes a high-temperature vessel and a quench ring assembly. Thequench ring assembly includes a main structural sub-assembly coupled toand circumferentially extending about the high-temperature vessel. Thequench ring assembly also includes a flow control sub-assembly coupledto the main structural sub-assembly and extending circumferentiallytherethrough. The quench ring assembly further includes a wearsub-assembly removably coupled to the main structural sub-assembly. Thewear sub-assembly includes a heat shield canopy extending over the flowcontrol sub-assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is schematic view of an exemplary integrated gasificationcombined cycle power generation system;

FIG. 2 is a schematic cross-sectional view of an exemplary syngas coolerthat may be used with the system shown in FIG. 1;

FIG. 3 is a schematic cross-sectional view of an exemplary quench ringassembly that may be used with the syngas cooler shown in FIG. 2; and

FIG. 4 is a flow chart of an exemplary method of maintaining the syngascooler shown in FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic diagram of an exemplary gasification facility, andmore specifically, is a schematic diagram of an exemplary integratedgasification combined-cycle (IGCC) power generation system 10. IGCCsystem 10 generally includes a main air compressor 12, an air separationunit (ASU) 14 coupled in flow communication to compressor 12, a gasifier16 coupled in flow communication to ASU 14, a syngas cooler 18 coupledin flow communication to gasifier 16, a gas turbine engine 20 coupled inflow communication with syngas cooler 18, and a steam turbine engine 22coupled in flow communication with syngas cooler 18. Alternatively, suchgasification facility is a portion of any facility in any suitableconfiguration that enables operation of gasifier 16, including, withoutlimitation, a chemical production plant.

In operation, compressor 12 compresses ambient air that is thenchanneled to ASU 14. In the exemplary embodiment, in addition tocompressed air from compressor 12, compressed air from a gas turbineengine compressor 24 is supplied to ASU 14. Alternatively, compressedair from gas turbine engine compressor 24 is supplied to ASU 14, ratherthan compressed air from compressor 12 being supplied to ASU 14. In theexemplary embodiment, ASU 14 uses the compressed air to generate oxygenfor use by gasifier 16. More specifically, ASU 14 separates thecompressed air into separate flows of oxygen (O2) and a gas by-product,sometimes referred to as a “process gas”. The O2 flow is channeled togasifier 16 for use in generating synthesis gases, referred to herein as“syngas” for use by gas turbine engine 20 as fuel, as described below inmore detail.

The process gas generated by ASU 14 includes nitrogen and will bereferred to herein as “nitrogen process gas” (NPG). The NPG may alsoinclude other gases such as, but not limited to, oxygen and/or argon.For example, in the exemplary embodiment, the NPG includes between about95% and about 100% nitrogen. In the exemplary embodiment, at least someof the NPG flow is vented to the atmosphere from ASU 14, and at leastsome of the NPG flow is injected into a combustion zone (not shown)within a gas turbine engine combustor 26 to facilitate controllingemissions of engine 20, and more specifically to facilitate reducing thecombustion temperature and reducing nitrous oxide emissions from engine20. In the exemplary embodiment, IGCC system 10 includes a NPGcompressor 28 for compressing the nitrogen process gas flow before beinginjected into a combustion zone (not shown) of gas turbine enginecombustor 26.

In the exemplary embodiment, gasifier 16 converts a mixture of fuelsupplied from a fuel supply 30, O₂ supplied by ASU 14, steam, and/orliquid water, and/or slag additive into an output of syngas for use bygas turbine engine 20 as fuel. Although gasifier 16 may use any fuel,gasifier 16, in the exemplary embodiment, uses coal, petroleum coke,residual oil, oil emulsions, tar sands, and/or other similar fuels.Furthermore, in the exemplary embodiment, syngas generated by gasifier16 includes carbon monoxide, hydrogen, and carbon dioxide. In theexemplary embodiment, gasifier 16 is an entrained flow gasifier,configured to discharge syngas, slag, and fly ash vertically downwardinto syngas cooler 18. Alternatively, gasifier 16 may be any type andconfiguration that facilitates operation of syngas cooler 18 asdescribed herein.

In the exemplary embodiment, syngas generated by gasifier 16 ischanneled to syngas cooler 18 to facilitate cooling the syngas, asdescribed in more detail below. The cooled syngas is channeled fromcooler 18 to a clean-up device 32 that facilitates cleaning the syngasbefore it is channeled to gas turbine engine combustor 26 for combustiontherein. Carbon dioxide (CO₂) may be separated from the syngas duringclean-up and, in the exemplary embodiment, may be vented to theatmosphere. Gas turbine engine 20 drives a first generator 34 thatsupplies electrical power to a power grid (not shown). Exhaust gasesfrom gas turbine engine 20 are channeled to a heat recovery steamgenerator (HRSG) 36 that generates steam for driving steam turbine 22.Power generated by steam turbine 22 drives a second generator 38 thatalso provides electrical power to the power grid. In the exemplaryembodiment, steam from heat recovery steam generator 36 may be suppliedto gasifier 16 for generating syngas.

Furthermore, in the exemplary embodiment, system 10 includes a pump 40that supplies heated water from HRSG 36 to syngas cooler 18 tofacilitate cooling syngas channeled from gasifier 16. The heated wateris channeled through syngas cooler 18 wherein water is converted tosteam. Steam from cooler 18 is then returned to HRSG 36 for use withingasifier 16, syngas cooler 18, and/or steam turbine 22.

FIG. 2 is a schematic cross-sectional view of a lower portion of anexemplary syngas cooler 100 that may be used with system 10 (shown inFIG. 1). Syngas cooler 100 is an exemplary embodiment of syngas cooler18 (shown in FIG. 1) and is a radiant syngas cooler (RSC). Syngas cooler100 includes a plurality of heat exchange devices, such as, but notbeing limited to, a heat exchange wall 104 and/or platen assemblies (notshown), positioned within a cooler shell 102. In the exemplaryembodiment, heat exchange wall 104 substantially isolates shell 102 fromsyngas 110 flowing through cooler 100. Also, in the exemplaryembodiment, shell 102 has a substantially circular cross-sectional shapehaving a longitudinal axis, or centerline 106. Alternatively, shell 102may have any cross-sectional shape that facilitates operation of cooler100 as described herein. A main syngas flowpath 108 is defined withincooler 100 along which syngas 110 and/or particulates 112 generallyflow. In some embodiments, shell 102 and wall 104 are fabricated fromany material that facilitates preventing syngas 110 and particulatematerial 112 from substantially adhering to shell 102 and wall 104.

In the exemplary embodiment, flowpath 108 is generally aligned parallelwith centerline 106. Although syngas 110 and particulates 112 are shownas separate flows, it will be understood that particulates 112 may beentrained with and/or suspended within syngas 110 such that particulates112 and syngas 110 constitute a combined flow. Furthermore, as usedherein, the terms “upstream” and “downstream” are defined with respectto main syngas flowpath 108, such that a top (not shown) of cooler 100is considered to be “upstream” from a bottom 114 of cooler 100. Also, asused herein, particulates 112 is defined to include molten ashparticulates, char, and fly ash particulates.

Cooler 100 also includes a quench chamber 116 that is downstream fromthe heat exchange devices. Chamber 116 facilitates rapidly coolingsyngas 110 and/or particulates 112. More specifically, a lower wall 118separates quench chamber 116 from a heat exchange section 120 of cooler100 including the heat exchange devices (as described above) therein. Inthe exemplary embodiment, lower wall 118 is formed from a plurality ofheat exchange tubes (not shown). Alternatively, in other embodiment,lower wall 118 is fabricated from a refractory liner material. Moreover,in some embodiments, quench chamber 116 and lower wall 118 arefabricated from any material that facilitates preventing syngas 110 andparticulate material 112 from substantially adhering to quench chamber116 and lower wall 118. In the exemplary embodiment, lower wall 118 issubstantially conical and tapers inwardly, or converges from an upstreamend 122 of lower wall 118 to a downstream end 124 of lower wall 118.Moreover, upstream end 122 may be coupled to, and/or positioned adjacentto, a downstream end 126 of heat exchange wall 104. Alternatively, lowerwall 118 may be coupled to any other suitable component within syngascooler 100 that enables operation of cooler 100 as described herein.

In the exemplary embodiment, quench chamber 116 includes a dip tube 128,a quench ring assembly 129, an isolation tube 130, a splash plate 132, afluid retention chamber, or water bath 134, a sump 136, a blowdown line138, a water bath fluid makeup supply line (not shown) and at least onesyngas outlet 140. In some embodiments, dip tube 128 and isolation tube130 are fabricated from any material that facilitates preventing syngas110 and particulate material 112 from substantially adhering to dip tube128 and isolation tube 130.

Water bath 134 includes bath water 142, wherein although water 142 isdescribed herein as the fluid used to quench syngas 110 and/orparticulates 112, any suitable non-reactive fluid may be used forquenching. In the exemplary embodiment, quench ring assembly 129 issituated at an upstream end 150 of dip tube 128, and is used to wet andcool an inner wall 174 of dip tube 128, as well as facilitate coolingand scrubbing of syngas 110 and particulates 112. Upstream end 150 iscoupled to quench ring assembly 129 through a circumferential weld (notshown). Alternatively, upstream end 150 is coupled to quench ringassembly 129 through any coupling method that enables operation ofquench ring assembly 129 and cooler 100 as described herein.

To facilitate mitigating deposition of molten particulates 112 on diptube 128 due to direct contact of relatively hot particulates 112 withdip tube 128, dip tube 128, as well as quench ring assembly 129, arepreferably somewhat recessed relative to downstream end 124 of lowerwall 118.

Dip tube 128, quench ring assembly 129, and isolation tube 130 each havea substantially circular cross-section. In the exemplary embodiment, diptube 128, quench ring assembly 129, and isolation tube 130 aresubstantially concentrically aligned with centerline 106. As such, aprimary quench zone 144 is defined within dip tube 128, a firstsubstantially annular passage 146 is defined between dip tube 128 andisolation tube 130, and a second substantially annular passage 148 isdefined between isolation tube 130 and shell 102.

Moreover, in the exemplary embodiment, upstream end 150 of dip tube 128is coupled proximate to an upstream end 151 of splash plate 132, anupstream end 152 of isolation tube 130 is coupled proximate to adownstream end 153 of splash plate 132, and a downstream end 154 of diptube 128 is positioned upstream from a downstream end 156 of isolationtube 130. Each upstream end 150 and 151 is positioned proximate to lowerwall 118. Specifically, in the exemplary embodiment, each upstream end150 and 151 is positioned proximate to downstream end 124 of lower wall118. Downstream end 154 of dip tube 128 extends into water bath 134,thereby facilitating quenching and scrubbing of syngas 110 andparticulates 112 exiting downstream end 154 by water 142.

Downstream end 156 of isolation tube 130 also extends into water bath134. In the exemplary embodiment, downstream end 154 of dip tube 128 isserrated to help distribute syngas 110 as it enters into water bath 134beneath dip tube 128. Similarly, in the exemplary embodiment, downstreamend 156 of isolation tube 130 is serrated to help syngas 110 to flowwithin water bath 134, between annular passage 146 and annular passage148. In an alternative embodiment, downstream ends 154 and/or 156 oftubes 128 and/or 130, respectively, may have any suitable shape thatfacilitates operation of cooler 100 as described herein.

A third passage 160 is defined between splash plate 132 and shell 102.Splash plate 132 facilitates retaining syngas 110 and water 142 withinisolation tube 130. In the exemplary embodiment, splash plate 132 isgenerally annular and extends between upstream end 151 and downstreamend 153. In the exemplary embodiment, downstream end 153 of splash plate132 is coupled proximate to upstream end 152 of isolation tube 130and/or to heat exchange wall downstream end 126. In the exemplaryembodiment, splash plate 132 is generally frusto-conical. Splash plate132 is fabricated from any material that facilitates preventing syngas110, water 142, and particulate material 112 from substantially adheringto splash plate 132. As such, splash plate 132 facilitates preventingaccumulation of particulates 112 in syngas 110 as well as knockout ofnon-evaporated entrained water droplets, such that particulates 112 andwater droplets (not shown) fall into water bath 134 after contactingsplash plate 132.

At least one syngas outlet 140 is defined between splash plate 132 andshell 102 such that syngas outlet 140 is in flow communication withthird passage 160. Outlet 140 channels syngas 110 from isolation tube130 to a component outside of shell 102. As shown in FIG. 2, cooler 100includes two outlets 140 extending from within isolation tube 130through splash plate 132 and through shell 102. Although only twooutlets 140 are shown in FIG. 2, alternatively, cooler 100 may includeany number of outlets 140 that facilitate operation of cooler 100 asdescribed herein.

In the exemplary embodiment, each outlet 140 is a cylindrical tube thathas a generally arcuate cross-sectional profile extending between afirst end 162 and a second end 164. Alternatively, outlet 140 may haveany shape that facilitates operation of cooler 100 as described herein.Specifically, in the exemplary embodiment, outlet 140 extends from firstend 162, positioned within isolation tube 130 near upstream end 152,through splash plate 132, and through shell 102. In the exemplaryembodiment, outlet second end 164 may be coupled to cleanup device 32(shown in FIG. 1), gas turbine engine 20 (shown in FIG. 1), and/or anyother suitable component that facilitates operation of system 10 andcooler 100 as described herein.

In the exemplary embodiment, each outlet 140 includes at least one sprayinjector 173 coupled thereto that channels a spray fluid stream 177 intooutlet 140. Specifically, each spray injector 173 is coupled to an innersurface 175 of outlet 140. Alternatively, each spray injector 173 iscoupled to any surface that facilitates operation of cooler 100 asdescribed herein. Moreover, in the exemplary embodiment, spray injector173 is coupled within outlet 140 such that flow discharged therefrom isdischarged longitudinally downward substantially in diametric oppositionagainst the longitudinally upward flow of syngas 110 into outlet 140.Alternatively, at least one spray injector 173 is oriented to dischargefluid stream 177 in a direction that is at least partially oblique to atleast a portion of syngas 110 flow within outlet 140. Also,alternatively, at least one spray injector 173 is oriented to dischargefluid stream 177 in a direction that is substantially parallel to andcoincident with at least a portion of syngas 110 flow within outlet 140.Further, alternatively, at least one spray injector 173 is oriented inany direction that facilitates operation of syngas cooler 100 asdescribed herein. Moreover, alternatively, injector 173 is a gasinjector that forms a gas quenching stream 177.

Moreover, each spray injector 173 is selectively operable as describedabove. Typically, in the exemplary embodiment, spray injector 173 is incontinuous operation with substantially constant flow rates. Under someconditions, fluid flow rates may be modulated as a function of a mode ofoperation. Alternatively, any periodicity of spray operation with anyfluid flow rates that facilitate operation of cooler 100 as describedherein are used. When each spray injector 173 is in operation, sprayinjector 173 injects fluid spray stream 177 as described above. Sprayinjector 173 and spray stream 177 facilitate eliminating non-evaporatedentrained water droplets, and substantially reduces and/or preventsaccumulation of particulates 112, and/or water 142 from along wallsand/or surfaces of components within cooler 100 that include, but arenot limited to, an outer surface 178 of dip tube 128, an inner surface180 of isolation tube 130, and at least a portion of surface 175 ofoutlet 140.

Furthermore, spray injector 173 and stream 177 facilitate furthercooling of syngas 100. Moreover, spray injector 173 and spray stream 177may be adjusted to mitigate accumulation and agglomeration ofparticulates 112 within water bath 134 and sump 136. As such, with lessaccumulation on walls and/or surfaces of components within cooler 100,as well as less agglomeration in water 142, less plugging and/or foulingof such components occurs. Outlet 140 includes any number of sprayinjectors 173 that enables cooler 100 to function as described herein.In an alternative embodiment, outlet 140 does not include any sprayinjectors 173. In a still further alternative embodiment, at least onespray injector 173 is coupled to splash plate 132, isolation tube 130,and/or any suitable component of cooler 100 that facilitates operationof cooler 100 as described herein.

As described above, fluid 177 discharged from spray injector 173 mayflow downstream into water bath 134. In the exemplary embodiment, waterbath 134 includes water 142, sump 136, and blowdown line 138. Water bath134 forms a portion of quench chamber 116 that is configured to retainwater 142 therein. Although water bath 134 is shown and described ashaving water 142 contained therein, water bath 134 may include suitablefluids other than water 142 and still be considered to be a “waterbath.” Moreover, spray injectors 173 are coupled in flow communicationwith a fluid source (not shown), wherein such fluid that forms spraystreams 177 is compatible with the fluids within water bath 134 andstreams 177 mix within water 142 such that water 142 is considered toinclude fluids from streams 177, if any.

Downstream from dip and isolation tube ends 154 and 156, respectively,sump 136 is defined within water bath 134. More specifically, sump 136may include a collection cone (not shown) coupled within shell 102 and acylindrical sump outlet 170 that extends through shell bottom 114. Sumpoutlet 170 may be coupled to a slag crusher (not shown), a lock hopper(not shown), a pump (not shown), and/or any other wet particulatehandling and/or removal device that facilitates operation of system 10as described herein.

Also, in the exemplary embodiment, blowdown line 138 extends from waterbath 134 through shell 102, and is configured to regulate the volume ofwater 142 within water bath 134. The water (not shown) that is blowndown through blowdown line 138 is normally sent to a process waterhandling system (not shown) that enables the beneficial reuse of atleast some of the blown down water. However, the blown down water may besent to any suitable component, system, and/or location that facilitatesoperation of system 10 as described herein.

During system operation, syngas 110 with particulates 112 is channeledfrom gasifier 16 to cooler 100. Syngas 110 flows through the heatexchange devices within cooler 100 and into quench chamber 116. Morespecifically, lower wall 118 of cooler 100 channels syngas 110 withparticulates 112 into primary quench zone 144, wherein syngas 110 flowspast downstream end 124 of lower wall 118 and along inner wall 174 ofdip tube 128, into water bath 134. Plugging of dip tube 128 is mitigatedby the combined effects associated with the recessed position of innerwall 174 relative to downstream end 124 of lower wall 118, therelatively lower temperature of wall 174 as compared to particulates112, which is partially cooled by water 142 external to dip tube 128,and relatively high momentums of the larger molten particles ascontrasted with relatively lower momentums of the smaller coolerparticles. Moreover, in the exemplary embodiment, quench ring assembly129 wet and cool inner wall 174 of dip tube 128, as well as facilitatecooling and scrubbing of syngas 110 and particulates 112.

Particulates 112 that are solidified are referred to herein assolidified slag 176. Solidified slag 176 is formed after falling throughprimary quench zone 144 into water bath 134 and is discharged fromcooler 100 through sump 136 via sump outlet 170. Syngas 110 andremaining particulates 112 rise up through passage 146 where syngas 110is scrubbed further by one or more sprays 177, causing additionalparticulates 112 to fall and be captured in water bath 134, while syngas110 and any remaining particles 112 exit syngas cooler 100 through oneor more nozzles 140. In the exemplary embodiment, syngas 110 and/or,particulates 112 exiting water bath 134 are at a reduced temperaturerelative to syngas 110 and/or particulates 112 entering water bath 134.

Scrubbed syngas 110, which is substantially without particulate 112and/or entrained water 142, is channeled from first passage 146 throughoutlet 140 for use within system 10. In the exemplary embodiment, sprayinjector 173 sprays syngas 110 with fluid spray 177 before syngas 110 ischanneled through outlet 140. As such, the fluid from spray injector 173facilitates preventing accumulation of particulates 112 on surface 175of outlet 140 and also facilitates preventing plugging of isolation tube130, and/or outlet 140. Moreover, fluid spray 177 facilitates anyfurther separation of particulates 112 from syngas 110 and any furthercooling of syngas 110.

FIG. 3 is a schematic cross-sectional view of quench ring assembly 129that may be used with syngas cooler 100 (shown in FIG. 2). In theexemplary embodiment, quench ring assembly 129 has a substantiallycircular cross-section that is substantially concentrically aligned withcenterline 106 (shown in FIG. 2). Quench ring assembly 129 includes amain structural sub-assembly 202 coupled to downstream end 124 of lowerwall 118 (shown in FIG. 2). As described above, in the exemplaryembodiment, lower wall 118, including downstream end 124, is formed froma plurality of heat exchange tubes (not shown). Main structuralsub-assembly 202 is fabricated through a forging process. Alternatively,main structural sub-assembly 202 is fabricated through any process thatenables operation of quench ring assembly 129, including, withoutlimitation, welding and machining of arcual portions (not shown) of mainstructural sub-assembly 202.

In the exemplary embodiment, main structural sub-assembly 202 isfastened to downstream end 124 through a plurality of circumferentialfasteners (not shown) that are inserted though aligned fastener holes204 and 206 defined through downstream end 124 and main structuralsub-assembly 202, respectively. Alternatively, any method of couplingmain structural sub-assembly 202 to cooler shell 102 that enablesoperation of quench ring assembly 129 as described herein is used,including, without limitation, seal welding.

Also, in the exemplary embodiment, quench ring assembly 129 includes aflow control sub-assembly 210 coupled to main structural sub-assembly202 and extending circumferentially therethrough. Flow controlsub-assembly 210 includes two semi-circular ring segments (not shown)coupled through an interference, or friction fit to main structuralmember 202.

Further, in the exemplary embodiment, quench ring assembly 129 includesa wear sub-assembly 220 removably coupled to main structuralsub-assembly 202. Wear sub-assembly 220 is a unitary, substantiallycircular piece that is coupled to main structural sub-assembly 202through one of a circumferential non-bonded joint 221 and acircumferential seam weld 222 positioned at a circumferential couplingsite 223 defined at the contact point of wear sub-assembly 220 with mainstructural sub-assembly 202. Wear sub-assembly 220 includes a heatshield canopy 224 extending over flow control sub-assembly 210.Circumferential coupling site 223 is positioned a predetermined distanceD from heat shield canopy 224. Distance D has any value that facilitatessufficient set-back either of non-bonded joint 221 and seam weld 222from the deleterious effects of syngas 110 and particulates 112. Heatshield canopy 224 is substantially C-shaped and is configured to extendover flow control sub-assembly 210 along the entire circumference (notshown) of flow control sub-assembly 210. Alternatively, wearsub-assembly 220 includes a plurality of wear segments (not shown)configured to at least partially extend over a portion of flow controlsub-assembly 210.

Moreover, in the exemplary embodiment, quench ring assembly 129 includesa plurality of separation devices 230 coupled to, and extending between,flow control sub-assembly 210 and heat shield canopy 224. Apredetermined number of separation devices 230 are circumferentiallypositioned at predetermined spacings (not shown). Separation devices 230facilitate defining a cooling fluid flow channel 240 between flowcontrol sub-assembly 210 and heat shield canopy 224. Cooling fluid flowchannel 240 defines a separation distance 242 extending between flowcontrol sub-assembly 210 and heat shield canopy 224. Channel 240 definesany distance value that facilitates sufficient cooling fluid flow valuesthat enable operation of quench ring assembly 129 and syngas cooler 100as described herein. Separation devices 230 are high-temperature ballbearings. Alternatively, separation devices 230 may be any devices thatenable operation of quench ring assembly 129 as described herein. Also,alternatively, separation devices 230 may be positioned downstreamwithin cooling fluid flow channel 240 to extend between main structuralsub-assembly 202 and heat shield canopy 224.

Also, in the exemplary embodiment, flow control sub-assembly 210 iscoupled to wear sub-assembly 220 through a plurality of flow plates 243(only one shown) that at least partially define a plurality of channels244. Channels 244 are coupled in flow communication with cooling fluidflow channel 240. Each of flow plates 243 includes a substantiallyvertical upstream side 245 and a curved downstream side 246. Also, eachof flow plates 243 include an upper side 247 that is coupled to wearsub-assembly 220 through any method that enables operation of quenchring assembly 129 as described herein, including, without limitation,welding, an interference, or friction fit within a slot (not shown)defined in wear sub-assembly 220, and an interference fit with wearsub-assembly 220 without a slot. Further, each of flow plates 243include a lower side 248 that is coupled to flow control sub-assembly210 through any method that enables operation of quench ring assembly129 as described herein, including, without limitation, welding, aninterference, or friction fit within a slot (not shown) defined in flowcontrol sub-assembly 210, and an interference fit with flow controlsub-assembly 210 without a slot. Coupling flow plates 243 to wearsub-assembly 220 and coupling flow plates 243 to flow controlsub-assembly 210 facilitates removal and replacement of wearsub-assembly 220 and flow control sub-assembly 210 together to decreaseinterference with and/or dislodging of main structural sub-assembly 202.

Further, in the exemplary embodiment, syngas cooler 100 includes aplurality of cooling fluid inlet pipes 250 that each define a coolingfluid inlet passage 252. A predetermined number of cooling fluid inletpipes 250 are circumferentially positioned at predetermined spacings(not shown). Cooling fluid inlet pipes 250 are coupled to mainstructural sub-assembly 202 and cooler shell 102. Main structuralsub-assembly 202 and wear sub-assembly 220 define a circumferentialcooling fluid manifold 260 coupled in flow communication with eachcooling fluid inlet passage 252. Circumferential cooling fluid manifold260 is coupled in flow communication with cooling fluid flow channel 240through channels 244.

Moreover, as described above, in the exemplary embodiment, dip tube 128is coupled to main structural sub-assembly 202 at upstream end 150.

During system operation, syngas 110 with particulates 112 is channeledfrom gasifier 16 (shown in FIG. 2) to cooler 100. Syngas 110 withparticulates 112 flow into primary quench zone 144 along inner wall 174of dip tube 128, into water bath 134 (shown in FIG. 2). Plugging of diptube 128 is mitigated by quench ring assembly 129 wetting and coolinginner wall 174. Specifically, cooling fluid 270 is channeled throughcooling fluid inlet pipes 250 into cooling fluid inlet passages 252.Cooling fluid 270 is then channeled into circumferential cooling fluidmanifold 260, into cooling fluid flow channel 240 through channels 244,and then onto cooling inner wall 174.

FIG. 4 is a flow chart of an exemplary method 300 of maintaining syngascooler 100 (shown in FIG. 2). At least a portion of circumferentialnon-bonded joint 221 and/or circumferential seam weld 222 positioned onquench ring assembly 129 that couples wear sub-assembly 220 to mainstructural member 202 at circumferential coupling site 223 is broken302. Such breaking 302 of circumferential seam weld 222 may includegrinding out at least a portion of the circumferential seam weld 222. Aleast a portion of wear sub-assembly 220 and a portion of flow controlsub-assembly 230 are removed 304 from main structural member 202. Atleast one replacement portion of wear sub-assembly 220 is provided 306either through a refurbished wear sub-assembly 220 or a new wearsub-assembly 220. The replacement portion of wear sub-assembly 220 ispositioned 308 to extend over at least a portion of flow controlsub-assembly 230 and to abut main structural member 202 proximatecircumferential coupling site 223. The replacement portion of wearsub-assembly 220 is coupled 310 to main structural member 202 through atleast one of circumferential non-bonded joint 221 and/or circumferentialseam weld 222.

In contrast to known quench rings and replacement methods, the quenchrings and replacement methods as described herein facilitate improvingthe efficiency of replacement maintenance activities without having todisconnect the entire quench ring from a gasifier cooler dip tube.Specifically, in contrast to known quench rings and replacement methods,the quench rings and replacement methods as described herein includeremoving only a radially innermost portion of the quench ring that isexposed to the highest temperatures and most erosive particulate flow.More specifically, a worn wear sub-assembly that includes a heat shieldcanopy and a coupled flow control-subassembly is removed and either arefurbished or a new wear sub-assembly and heat shield canopy isinstalled over the flow control-subassembly and all are reinstalled inthe quench ring as a unit. The remainder of the quench ring remainsattached to the dip tube, thereby decreasing a potential formisalignment of quench ring components as may be induced by the currentrepair practices. Therefore, maintenance activities associated withquench rings are decreased in scope, time, and cost.

Described herein are exemplary embodiments of quench rings thatfacilitate improved commercial operation over that of known quenchrings. The above-described methods, apparatus, and systems facilitatereducing maintenance activities associated with planned outages. Suchmethods, apparatus, and systems also facilitate reducing unnecessaryquench ring disassembly as compared to known quench rings. Specifically,the above-described methods, apparatus, and systems enable relativelyfast and efficient replacement of worn wear sub-assemblies that includea heat shield canopy with either a refurbished or a new wearsub-assembly and heat shield canopy. A coupled flow control sub-assemblyis also removed with the wear sub-assembly. Also, specifically, theremainder of the quench ring remains in place, thereby decreasing apotential for misalignment of quench ring components. Therefore,maintenance activities associated with quench rings are decreased inscope, time, and cost.

An exemplary technical effect of the methods, systems, and apparatusdescribed herein includes at least one of (a) decreasing unnecessaryquench ring disassembly, removal, and reassembly; and (b) decreasing apotential for misalignment of quench ring components.

The methods, apparatus, and systems described herein are not limited tothe specific embodiments described herein. For example, components ofeach system and/or steps of each method may be used and/or practicedindependently and separately from other components and/or stepsdescribed herein. In addition, each component and/or step may also beused and/or practiced with other assemblies and methods.

While the invention has been described in terms of various specificembodiments, those skilled in the art will recognize that the inventioncan be practiced with modification within the spirit and scope of theclaims.

What is claimed is:
 1. A quench ring assembly for a high-temperaturevessel comprising: a main structural sub-assembly coupled to at leastone lower wall tube; a flow control sub-assembly coupled to said mainstructural sub-assembly and extending circumferentially therethrough;and a wear sub-assembly removably coupled to said main structuralsub-assembly, said wear sub-assembly comprising a heat shield canopyextending over said flow control sub-assembly.
 2. The quench ringassembly in accordance with claim 1, wherein said wear sub-assemblycomprises at least one of a circumferential non-bonded joint and acircumferential seam weld coupling said wear sub-assembly to said mainstructural sub-assembly, said at least one of a circumferentialnon-bonded joint and a circumferential seam weld is positioned apredetermined distance from said heat shield canopy.
 3. The quench ringassembly in accordance with claim 1 further comprising at least oneseparation device coupled to and extending between said flow controlsub-assembly and said heat shield canopy.
 4. The quench ring assembly inaccordance with claim 1, wherein: said main structural sub-assemblydefines a circumferential manifold coupled in flow communication with atleast one cooling fluid inlet passage; and said flow controlsub-assembly and said heat shield canopy define a controlled coolingfluid flow channel therebetween, said controlled cooling fluid flowchannel coupled in flow communication with said circumferentialmanifold.
 5. The quench ring assembly in accordance with claim 1,wherein said at least one flow control sub-assembly comprises twosemi-circular ring segments aligned to said main structural member. 6.The quench ring assembly in accordance with claim 1, wherein said wearsub-assembly comprises a plurality of wear segments, wherein each ofsaid wear segments is configured to at least partially extend over saidflow control sub-assembly.
 7. A method of maintaining a synthesis gas(syngas) cooler for use within a gasifier system, said methodcomprising: breaking at least a portion of at least one of acircumferential non-bonded joint and a circumferential seam weld on aquench ring assembly that couples a wear sub-assembly to a mainstructural member at a circumferential coupling site; removing at leasta portion of the wear sub-assembly and a flow control sub-assemblycoupled thereto from the main structural member; providing at least onereplacement portion of the wear sub-assembly; positioning the at leastone replacement portion of the wear sub-assembly to extend over at leasta portion of the flow control sub-assembly and to abut the mainstructural member proximate the circumferential coupling site; andcoupling the at least one replacement portion of the wear sub-assemblyto the main structural member.
 8. The method in accordance with claim 7,wherein breaking at least a portion of a circumferential seam weldcomprises grinding out the at least a portion of the circumferentialseam weld.
 9. The method in accordance with claim 7, wherein providingthe at least one replacement portion of the wear sub-assembly comprisesat least one of: refurbishing the at least a portion of the wearsub-assembly removed from the quench ring assembly; and providing atleast a portion of a new and unused wear sub-assembly.
 10. The method inaccordance with claim 7 further comprising separating the wearsub-assembly from the flow control sub-assembly comprising separating atleast one flow plate from one of the wear sub-assembly and the flowcontrol sub-assembly.
 11. The method in accordance with claim 10,wherein separating at least one flow plate from one of the wearsub-assembly and the flow control sub-assembly comprises at least oneof: breaking a weld between the at least one flow plate and the wearsub-assembly; breaking a weld between the at least one flow plate andthe flow control sub-assembly; disengaging the at least one flow platefrom a slot defined in the wear sub-assembly; and disengaging the atleast one flow plate from a slot defined in the flow controlsub-assembly.
 12. The method in accordance with claim 11, whereinseparating the wear sub-assembly from the flow control sub-assemblyfurther comprises removing at least one separation device coupled to andextending between the flow control segment and the wear sub-assembly.13. The method in accordance with claim 7, wherein positioning the atleast one replacement portion of the wear sub-assembly to extend over atleast a portion of the flow control sub-assembly comprises defining acooling fluid flow channel between the at least one replacement portionof the wear sub-assembly and the at least a portion of the flow controlsub-assembly.
 14. The method in accordance with claim 7 furthercomprising maintaining an alignment between the main structural member,at least one cooling fluid inlet fixture, a dip tube, and a hightemperature vessel.
 15. A gasifier system comprising: at least onegasifier configured to produce a synthesis gas (syngas); and at leastone syngas cooler coupled in flow communication with said gasifier, saidat least one syngas cooler comprising: a high-temperature vessel; and aquench ring assembly comprising: a main structural sub-assembly coupledto at least one lower wall tube; a flow control sub-assembly coupled tosaid main structural sub-assembly and extending circumferentiallytherethrough; and a wear sub-assembly removably coupled to said mainstructural sub-assembly, said wear sub-assembly comprising a heat shieldcanopy extending over said flow control sub-assembly.
 16. The gasifiersystem in accordance with claim 15, wherein said wear sub-assemblycomprises at least one of a circumferential non-bonded joint and acircumferential seam weld coupling said wear sub-assembly to said mainstructural sub-assembly, said at least one of a circumferentialnon-bonded joint and a circumferential seam weld is positioned apredetermined distance from said heat shield canopy.
 17. The gasifiersystem in accordance with claim 15 further comprising at least oneseparation device coupled to and extending between said flow controlsub-assembly and said heat shield canopy.
 18. The gasifier system inaccordance with claim 15, wherein: said main structural sub-assemblydefines a circumferential manifold coupled in flow communication with atleast one cooling fluid inlet passage; and said flow controlsub-assembly and said heat shield canopy define a controlled coolingfluid flow channel therebetween, said controlled cooling fluid flowchannel coupled in flow communication with said circumferentialmanifold.
 19. The gasifier system in accordance with claim 15, whereinsaid at least one flow control sub-assembly comprises two semi-circularring segments aligned to said main structural member.
 20. The gasifiersystem in accordance with claim 15, wherein said wear sub-assemblycomprises a plurality of wear segments, wherein each of said wearsegments is configured to at least partially extend over said flowcontrol sub-assembly.